Classical black hole solutions of general relativity contain spacetime singularities [1]},
which are expected to be removed in the quantum theory of the gravitational collapse of
a compact source (see, e.g., Refs. [2]}).
Moreover, charged and rotating classical black holes also contain a inner Cauchy horizon,
which signals a potential loss of predictability and also gives rise to mass inflation
at the perturbative level (see, e.g., Refs. [3]}).
These latter considerations are the underlying motivations for the
strong cosmic censorship conjecture [4]}, [5]},
which can be simply phrased as the fact that the evolution of some sufficiently regular
initial data should always give rise to a globally hyperbolic spacetime [6]}.
In particular, this conjecture implies that perturbations of the inner Cauchy horizon should
turn it into a curvature singularity.
